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55 lines
1.1 KiB
55 lines
1.1 KiB
<?php
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declare(strict_types = 1);
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namespace DASPRiD\Enum;
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use DASPRiD\Enum\Exception\CloneNotSupportedException;
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use DASPRiD\Enum\Exception\SerializeNotSupportedException;
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use DASPRiD\Enum\Exception\UnserializeNotSupportedException;
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final class NullValue
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{
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/**
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* @var self
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*/
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private static $instance;
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private function __construct()
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{
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}
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public static function instance() : self
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{
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return self::$instance ?: self::$instance = new self();
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}
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/**
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* Forbid cloning enums.
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*
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* @throws CloneNotSupportedException
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*/
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final public function __clone()
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{
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throw new CloneNotSupportedException();
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}
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/**
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* Forbid serializing enums.
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*
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* @throws SerializeNotSupportedException
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*/
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final public function __sleep() : void
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{
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throw new SerializeNotSupportedException();
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}
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/**
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* Forbid unserializing enums.
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*
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* @throws UnserializeNotSupportedException
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*/
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final public function __wakeup() : void
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{
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throw new UnserializeNotSupportedException();
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}
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}
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